Absorption chilling uses a refrigeration cycle that requires little or no electric input, because it does not employ a mechanical compressor. Instead, the refrigeration effect is produced through heating and cooling a circulating absorbent liquid. When a moderate temperature heat source is available and/or local electric costs are high, absorption refrigeration can be quite economical. The type of absorption chiller most familiar to the general public is the ‘propane refrigerator’, which is found in RV’s or at remote homesteads. In fact, absorption chilling is not a new concept. The first simple ammonia/water absorption chiller was built by Ferdinand Carre in 1846 and marketed as an ice-making machine